I hope this message finds you well, present circumstances excluded. I am a licensed attorney with over a decade of employment law experience. It is a pleasure to assist you today.The answer to your question depends entirely on the wording of the collective bargaining agreement between the union and the hospital. If the agreement gives the hospital the flexibility to make changes such as this one, then the language of the collective bargaining agreement would technically trump the working of your agreement to work the specified hours to which you agreed.You need to speak back with you union rep and ask him/her to provide to you the language in the collective bargaining agreement or other agreement with the hospital that allows this type of practice. It is likely there and the language is likely pretty broad and gives the hospital great discretion.That said, if it is not there, then technically speaking, the hospital does not have this right and it will then be up to the union to force the issue and make sure it does not happen.So, while you are right that it breaks your contract, it is not technically a breach of contract by the hospital if this is allowed under the overarching agreement they have with the union. If it is not a part of the agreement, then they have technically breached your contract.Let me know if you have any other questions or comments.Please rate my answer positively if you have been assisted at all.Best wishes going forward!